The fuel tanks of motor vehicles and the like tend to accumulate water, dirt and contaminated fuel for a number of reasons. Water accumulates in the fuel tanks because there is moisture which is present in the air within the fuel tank which remains in the air at elevated temperatures, but condenses out when the temperature is lowered since the air at the lower temperature is not capable of holding the moisture which was present at the higher temperatures. This water then contaminates the fuel in the tank and at very low temperatures is responsible for the gas line freeze ups which occur particularly when fuel tanks are permitted to remain relatively close to empty at low temperatures.
Water and dirt and contaminated fuel can be also introduced into the fuel tank of a motor vehicle when the fuel tank is filled with fuel which has water, dirt or other contaminants in it. The fuel can become contaminated with water through substantially the same process that takes place in the vehicle fuel tank. However, in this connection it is the moisture in the air in the service station tank that contaminates the fuel with water.
Obviously, fuel filters have been installed in motor vehicles to remove at least some of these contaminants. However, some of the contaminants still get through particularly water which may be in the fuel.
The effects of water, dirt and other contaminants on the operation of the motor vehicle's fuel system and engine will, of course, vary according to the type of contamination and the severity of the contamination, but the effects can result in fuel system and engine damage due to corrosion, abrasion and other adverse reactions as well as poor engine performance and possibily hard starting of the engine.
These effects can be particularly severe in the case of diesel motor vehicles since water and other contaminants can clog the fuel filter, particularly in cold weather, and block the filter so that it is virtually impossible to start the engine. In addition, damage can result to the fuel injectors and other parts of the diesel engine due to contaminated fuel. Recently, there have been numerous complaints about diesel engine repairs which can perhaps be related to contaminated diesel fuel which is apparently to some degree prevalent in the United States.
The present invention provides the means to eliminate the problems associated with the presence of contaminated fuel in the tanks of motor vehicles. Most of the contaminants, including water, in the fuel in the fuel tank of the motor vehicle are located in the bottom portion of the fuel tank. Unfortunately, there is presently no easy way to eliminate such contamination without pumping out the fuel tank or by draining it which may require the removal of the tank or other difficult procedures. With the present invention it is easy to periodically drain the contaminants from the fuel tank so as to keep the fuel tank free of contamination.